The present invention relates to broadband impedance matching, and more particularly for such impedance matching for use with circularly polarized (CP) antennas.
The standing wave ratio (SWR) requirements for a television transmitting antenna are very stringent. In particular, it is desired that the SWR not exceed 1.1:1 across a given television channel. When stacking bays of one particular CP antenna, it has been found that one wavelength spacing provides maximum gain, as shown in FIG. 8 of U.S. Pat. No. 4,031,536. However, for one embodiment of a slanted dipole type of array having multiple bays, this spacing makes the SWR versus frequency characteristic narrower in bandwidth and makes for greater radiation along the mast axis.
It is desirable to have an antenna with a broadband SWR characteristic which also decreases radiation along the mast axis.